Example embodiments relate to semiconductor memory devices, and more particularly, to nonvolatile memory devices and to methods of programming nonvolatile memory devices.
A semiconductor memory device is a memory device which is fabricated at least in part from semiconductors such as silicon (Si), germanium (Ge), gallium arsenide (GaAs), indium phosphide (InP), and the like. Semiconductor memory devices are generally classified as either volatile memory devices or nonvolatile memory devices.
Volatile memory devices are characterized by the loss of stored data when a power supply is interrupted. Examples of volatile memory devices include certain types of random access memory (RAM) such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), and the like. On the other hand, nonvolatile memory devices are characterized by the retention of stored data when a power supply is interrupted. Examples of nonvolatile memory devices include read only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable and programmable ROM (EEPROM), flash memory devices (including NOR type and NAND type), phase-change RAM (PRAM), magnetic RAM (MRAM), resistive RAM (RRAM), ferroelectric RAM (FRAM), and the like.